The relationship between the hottest solvent and s

2022-07-23
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The relationship between solvent and printing ink

solvent is an indispensable material in plate printing, which has a key impact on printing production and print quality. In printing, the solvent and printing ink are closely related, which must be paid full attention to. Here are some brief descriptions

1. Functions of solvents in plate printing

(1) dissolving resin: different solvents (polar and non-polar) are used to dissolve different resins according to their needs

(2) fluidity: similar products produced by different manufacturers have different solubility, which directly affects the viscosity of the ink

(3) gloss: why does the pressure of the same or rubber material testing machine with different volatilization rates not go up? When different solvents are released in the printing ink film, they will cause atomization and whitening of the ink film, thus affecting the gloss of the printing surface

(4) drying time: due to different printing methods selected during printing, the interaction of polymer materials chelating zn2+ with 4-butylammonium bromide, the difference of printing environment and climatic conditions and the needs of formula, the boiling point of solvent is different to provide appropriate drying time

(5) residual solvent: some solvents with low affinity with resin help to prolong the opening time of printing ink film and reduce the residual solvent

2. Setting of solvent on printing ink characteristics

(1) solvent: the solvent used to dissolve the stable viscosity of the resin in accordance with the basic conditions of ink quality during the production of ink

(2) cosolvent: a solvent with good solubility in the main solvent, but slightly poor in other conditions, which can assist in solving some shortcomings

(3) diluent: it has no dissolving power to the resin of the ink itself, and has the function of dissolving after mixing with the main solvent to reduce the viscosity of the ink. The effect of diluting ink

3. The relationship between solvent solubility and printing

(1) for the ink itself, good solubility makes the ink appearance homogeneous, makes the ink have stable viscosity and fluidity, and is not easy to gelatinize. Adding appropriate cosolvent can fully obtain the effect of dilution and dispersion

(2) for printing equipment: adding inappropriate solvent can increase equipment friction and make printing equipment depreciation faster; At the same time, it may cause frequent downtime due to ink blocking. Start up operation, accelerate the wear of parts and reduce production efficiency

(3) relationship with printing ink film: the gloss, flatness, residue, fastness, ductility and adhesion of printing ink film must be fully considered in the selection of solvent

4. Precautions for solvent selection

(1) the commonly used solvents in printing inks are roughly divided into ketones, alcohols, benzene, esters, alkanes and so on. The main function of solvent is to dissolve resin and dilute ink. All kinds of inks should carefully select the appropriate soluble LEGO agent. For example, in the PVC system, ketones can be dissolved, benzene slightly expands, alcoholized, and attention must be paid to the selection

(2) solubility of the cosolvent: the function of the cosolvent is similar to that of the main solvent. Therefore, the correct cosolvent must be selected so as not to cause the ink to gelatinize, lose fluidity and viscosity

(3) original specification purity of solvent (percentage): the original specification and purity of solvent directly affect the dissolution and dilution of ink. If it is not the original solvent, it may contain a small amount of moisture or impurities, which will have a great impact on the quality of the printed matter, and may lead to the loss of gloss, poor adhesion and blocking of the printed surface

(4) the evaporation rate of the solvent directly affects the drying rate of the ink. Due to the rapid development of printing technology and printing speed, appropriate solvents should be carefully selected, otherwise the printing operability will be greatly affected, resulting in the phenomenon that the ink dries too fast and blocks the plate, and it is easy to stick back if it dries too slowly

(5) dispersion of solvent to pigments: the choice of solvent has a close relationship with the dispersion of pigments contained in the ink. If the wrong solvent is used, the pigments in the ink will also condense (reverse coarseness) and affect the color rendering, so that the color concentration will be reduced, and even the normal printing will not be possible

(6) solubility of solvent to resin: people are migratory birds. In actual printing, if the solubility of solvent is poor, the resin or ink will solidify and the fluidity will become poor

(7) separation of pigment by solvent: in the use of color matching ink, if the wrong solvent is selected, various colors in the ink will be dispersed inconsistently, resulting in color separation, floating color and other color separation phenomena

(8) when using cosolvent, if the solubility is too poor, it is easy to make the ink lose viscosity (poor fluidity), and it is easy to produce water ripple, poor adhesion and gloss during printing

(9) drying speed cost of solvent: the solvent volatilizes too fast during printing, which not only affects the normal printing, but also makes the solvent consume faster and increases the cost. If the solvent dries too slowly, it will slow down the production speed and increase the labor cost

(10) solvent blending: the blending ratio of solvent has a great impact on the solubility and speed. During blending, the components of main solvent and auxiliary solvent must be controlled according to specific needs, so that they can adjust the solubility and drying speed according to the needs of ink

(11) relationship between the use of solvent and air humidity: if quick drying solvent is used for printing with ink, when the temperature is above 90%, the solvent volatilizes too fast and absorbs a large amount of moisture in the air, resulting in poor ink fluidity, loss of gloss and poor adhesion of the printed matter

(12) appearance of solvent: if the appearance of solvent is poor (not clear or with color), it will directly affect the hue of printed matter and cause color variation. (trancy)

source: China ink technology

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